This invention relates to an electromagnetic pump for electricity-conducting fluids, comprising an external pipe around which a magnetic yoke is installed in the form of slotted plates in which a polyphase winding is housed consisting of induction coils with the same axis as the external pip and an internal pipe fitted inside the external pipe and with the same axis as the latter, and containing inside a magnetic core capable of creating with the polyphase winding a magnetic field applying a force to the fluid in the pipe between the two pipes so that it circulates axially.
This electromagnetic pump is described in document FR-A- No. 1 599 876.
The polyphase winding produces a slipping field whose lines flow through the duct and are closed by the magnetic core inside the duct. Under the effect of this axisymetric configuration variable field, circular currents are induced in the fluid in the duct and the reaction of these currents on the radial induction produces an axial motive force imparting movements of the fluid.
These pumps are used notably to pump liquid sodium used to cool nuclear reactors.
In all these pumps it is necessary to be able to dismantle the magnetic yoke and the windings without previously opening and fully draining the sodium circuit which may be radioactive.
For this purpose, in the known pump, the external pipe is cut off at the back and the circulation of the fluid after flowing in the duct is returned in the opposite direction in the axial section of the internal pipe. It is thus possible to release the yoke and winding from the back.
The efficiency of this pump is relatively low.